Balanced-pressure elevator.



G. F. STEEDMAN.

BALANOED PRESSURE ELBVATOR. APPLICATION FILED MAB. 12,1909.

Patented Aug. 31, 1909.

imi-,nn #STATES f PATENT GEORGE r. s'innnmamors'r. Louis, MISSOURI.'

' BALANcED-Pnnssunn Eraiva'roa specification cftea'eis Patent. PatentedAug. 31, 1909.

i A Application filed March 12, 1909.` Serial N`o482,938. y l

To all whom it may concern; A Y

Be it known that vI, GEORGE F. STEEDMAN, a citizen of the United States,`.residingat St. Louis, Missouri, `have invented acertain new and useful`Improvement in Balanced# Pressure Elevators, of` which the following isa full, clear, and exact 'descriptiomsuch as will enable others skilledin `the `art to which it appertainsto make and use the same. y 1v Thisinvention relates to pneumatic ele-v vators, and particularly pneumaticelevators in which the cylinder is directly under-5 neath the cage.,`

In my 'numerous priorpatents, I have.

shown several different types of pneumatic elevators. In the directtype, the `'cylinder is placed directly overthe elevatorcage, and

the piston rod is connected directly.to the.-

upper part of the cage.v the-'rope.type, the cage is lifted by means ofwire `rope' attached to the upperportion ofthe cage.`

In both the direct and ropetype elevators,

the piston rod is in tensionV and lifts the cage by pulling on it.

The types of der be` directly underneath or platform.

The object of my present invention is tol adapt the use of a pneumatic`hoisting cylin der to a direct-acting elevator, in which the cylinderis directly underneath the platform and raises the platform by pushingitlup-k ward.

A further object of my invention is to prof vide an elevator of andreliable. Y

The accompanying drawing represents an elevator' of this type andillustrates the preferred embodiment ofmy invention.

this type, whichis safe It is usually desirable inl elevators ofthisclass that the support on which the load' rests be in the nature ofa platform and` not" a cage. The luse of a shallow platform'ref quiresthat the `piston rod .be `sufficiently strong to support withoutdistortion they platform when theentire load is carried `near one end orside` thereof, which necessitates` a piston rod of comparatively largediam` eter. f

elevators just ydescribed are not suitable for certain special uses, as,lforV instance, what istermed a sidewalk :ele-` vator where itisnecessary that .the cylinthe elevator cage The figure of the drawing isa vertical sectional view `of an elevator, embodying my upresentinvention. i

Referring to said drawing, A designates the cageor platform of anelevator which travels on vertically disposed tracks 1, and BLdesignates the operating cylinder that is arranged underneath said cage.The piston 2in said cylinder has a `piston rod 3 connected to its upperface, and said rod projects through a stufling box 4,1 in the upper endofthe cylinder,and is connected to the lower sideof the cage A.

.Theactuating fluid, which is preferably air underfpressure, iscontained in a tank,

vnot shown,andrsaid tank communicates with fa supplyV pipe 5, that leadsto the casing 6 of a two-,waycontrolling valve C, said supply ipipe 1having "a branch" 7 that communicates `with the lower end of thecylinder. A pipe Sthat communicates with the upper end of the cylinder,leads to said valve casing 6, and said valve casing is provided with aneX- liaust `pipe 9, that communicates with the atmosphere.

The means employedin the elevator-herein shown for controlling theactuating fluid to and from thecylinder is similar to that shown in myprior patent No. 840,876, dated January 8th, 1907,so that I will onlybriefly describe the operation of said means.

' "The supply Apipe 5 -is provided with a check valve 5'f1V arrangedbetween the branch 7 and-the supply tank, so as to prevent the fluidfrom backing up into the supply tank,

and.- said 1Vbranch 7 leads to a speed-control-- "ling-box" 10, having apair of oppositely opening-cheek valves 11 and 12, that permit by thearrows.

valve 12, permits the fluid on the underside ofthe piston to exhaustfrom the lower end Vof the cylinder,-when `the cage descends.

Thev pipe 8 that is tappedinto the casing of the controllingvalve C,communicates with aspeed-controlling box 15 having an inwardly openingcheck valve 16- that cooperates with a pipe 16.a which leads to theuptend to move it in a direction -to raise the .10

.per end of thecylinderfsaid box also having an outwardly opening checkvalve l? that cooperates with a pipe 1.7.a whichleads to the upper endof the cylinder. As thebranch 7 from the supply pipe communicates atlall times with the lower end of the cylinder,V

theniotiueforce will be constantly exerted on the underside of thepistonl and thus cage.V

'Ehe direction of movement of: the cage 'is goyelned .by thecontrolling: valve4 C,

which is adapted to be turnedzinto such aV position, that. the fluid outhe upper.- .side

of f the pistony can escape through. the pipe 1.7?, .speed-.controllingbox 15..,.and pipe. 8 to the exhaust pip@ 9; that lende from the cas- Yingx of; the. controlling-valve. The elevator is so.. designedy .thatlthe cageV dees not stop betareenitsupper anellower levels., and whenthe; eageapproaeheszether of levels, its.

f' speed graduallyA reduced .by means. of

plungers 18` and l19 lon'the lower;and!upper` 7 Sidesnt; the .pist-enthatprojeet into cushioning chfunbers` ldfand 1.9a inthe heads of thevcylinde asshown and. v.clearly described ing ehaniherse When the Cageis at its upper level. and it Y is d.(Vesiredfto;have Vit desoend,thevalve C is: turned inteisueh. a position that commu.- nicati'on willbeestablished between the sup- Y ply pipe 5:. and the .pipe 8.,. thuspermitting upperY side off the. piston,V soi as 'to balance.

the fluid t0. enten the upper end-.of the. cylinder and..V exertdewnward, pressure 011 the the' upward pressure or force. that isv ex.-erted on the; lower side. ofthe piston.. In

f view. of.: the feet that the pieten lied is lelge and -scenneeted to.-theupper .Side of they piston, the. area of the upper, face of thepieten, is mush lessv than the ereafef the lenierface Of the piston, .sethat the. enge Wouldenetdeseend when it net provided with a leed,Y ifseme ineens. in addition to.

the. fluid. .thatis intredueed-- inta ,the upper.I endr of the eylinderVwere net. vprovided.,lier

@Verema-ing; the. eXeessifve pressure that. the.

fluid exerts en the under sdeiefzthe piston.

"' eel'eeed;.the upward; pressure.r that. the'. fluid Theneiere., I;have se designed 'the cage. and the, pistQnrOdthat the combined-weightofseineg'j plus the pnessunej that the Yfhuid; eX:

entsfon'the. upperside of the. piston Willv exentsen the unden 'side etthepsten rlhis resultcan. be accomplished; in va-riouswvays,

-suehi'fen example, es presiding. the enge. -with n heavy inenihen D.that is conneeted tothe cage,

0fthe ease. Seidjlnelnhen D eddseneugh.

Permanently set that it. terms part.

4equalized. In other words, the

weight to the cage, so, that the combined weightwoui' the cage andpiston rod will be suiicient to cause the cage to descend unthe pressureon both sides of the piston is pistou rod and empty cage have.suliicient weight to return themselves against the unbalanced forces'ofthe hoist, it beingunderstood, of course,

that the location of the piston rod on the. upper side of; the` piston4prevents .the forces of the hoist from being; in balance. I prefer to.use the member D.7 which isformed of iron or sonic other heavy material:and provided with recesses 2l. that, canv be filled withsoine.suitableheavy materialthat adds Weight te the. cage, thus. enabling. the peruiafnent weight on the pistonl rod to be. varied by placing ,material in therecesses of the nienibeul) or removing it therefrom. I do net uishte. heunderstood, however, that my hleadideais limited teithis exact construe.tion7 for the piston can be weighted in nllllr. ereue other ways,without departing from the. spirit lofjniy iilivention,

Inniy previousvpaten-ts, Iy have shown the use Qfthebeleneed pressureair. heist adapt..

ed to pneumatic elevators where the pistons aeten the Cage hapulling. Inthe type ef vel,ev'ater herein illustrated; namely, one 1n whichthepisten 11nd iseenneeted t0 the under side 0f the eege,-d.ireet airpressure has heretofore beenused but such an elevatoris not safe.

VIn an elevator of the character herein described, but operated on. theysingle actingprinciple, pressure would-be admitted to the lower sidel ofthe piston to raise the load and exhausted freni said lower sidetoilowen the load. If the empty cage were forced, upward,` onlycomparatively light air, pressure wouldbe required toraise the eage,rand

ifbswhenthe cagereaehed its upper level, the,

full, load the elevator isg designed fork were placed,` uponI the Gage,there. would not be suflicient lsustaining power underneathjthe piston.and2 the. cage would descend, until the air. inthe cylinderr wascompressed,` suiioiently to support the load. Witlt the. bal-` anoedhoist,` principle herein-k showlnhoweuer, the action isdecidedlydilferent. Air under full pressure is constantly admitted to the. lowersidevof the piston, anda-ir inust be exhausted; froin the upper sidelofthe pistou.A to

Vpermit the cage'to ascend, and whentlie cage.

hasreaolredA its uppeu limit, there. is the full.

supporting pressure exerted on the undenside offthepiston, and; the airall exhausted from the upper side ofi-thc pistonLsothat the full` loadcan be placed upon thecage im mediatelyl upon its arrivah at the, upperlimit. With this explanation, it is obvious.

rod would apparently `prohibit* the use` of" the balancedpressure'hoist, and itis only by means of the novel expedient of addingsufficient weight to the ordinary. rod and anced air hoist to elevatorsas herein described. y

I have spoken only of pneumatic elevators throughout, but it is apparentthat" steam Aor any gas under pressure canbe used in place of compressedair, and when I speak, in the claims, of pneumatic elevators, Iwish itto be understood that steam 'or any other gas under pressure can besubstituted.

Having thus described myinvention', what I claim as new and desire tosecure by Let-V ters Patent is: i j Y l. In a balanced pressure hoist, acylinder provided with a piston, a piston rod connect-` ed to the upperside of said piston and pro-V j ectng upwardly through the upper end'ofsaid cylinder, a direct connection between the lower end of the cylinderand a supply of fluid under pressure, and means for introducing fluidunder pressure intothe upper end of the cylinder to causethe piston tomove in one direction and for exhausting the fluid from the upper end ofthe cylinder to cause the piston to move in the" opposite direction, thepiston rod carrying a permanent load which is of sullicient weight tolcause said piston to descend when the actuating j fluid isintroducedinto the upper end of the cylinder. Y j

2. In a balanced pressure fluid-actuated hoist, a cylinder provided witha piston "having a piston rod that projects upwardlyV through the upperend of thecylinder, said rod being adapted to have a permanent loadimposed on the upper end thereof, the lowerv end of t-he cylinder beingin constant comp-` munication with a supply of fluid under pressure, andmeans for introducing a balancmg pressure into the upper end `of thecylinder and exhausting it therefrom, the

weight of the piston rod and the permanent load thereon being sulficientto cause the load to descend when the pressure on the two sides of thepiston is equalized.` j

3. In a balanced pressure elevator,a cylinder provided with a piston,apiston rod connected to the upper side of said piston and projectingupwardly through a stuffing box in the upper end of the cylinder, a cageor supporting platform connected to the upper end of said piston rod,meansfor` establishing a direct connection betweenvthe lower end of thecylinderand a supply of fluid under pressure so that upward pressurewill be constantly exerted on the lower side of the piston, and meansfor admitting a fluid' under pressure into the upper end of the,

cylinder and exhausting it therefrom, the weightof` 'said cage andpiston rod being suliicient to cause the cage to descend when thepressure of the actuating fluid on the two sidesof the piston isequalized. cage that I have been abletoemploythe bal- 4, Ina -balancedpressure Huid-actuated elevator, a cage, a cylinder arranged under thecage andprovided with a piston, a rod connected to the upper side ofsaid piston for sustaining the entire weight of said cage, said rodbeing `of great enough cross sectional area that it will not bend whenthe cage 1s loaded unevenly, means for establishing direct `connectionbetween the lower end of the cylinder and a supply of fluid underpressure, a controlling valve for admitting fluid under pressure intothe upper end of the cylinder andfor exhausting it therefrom, and apermanent weight carried by said cage to compensate for the space whichthe piston rod takes up in the cylinder and thus cause the cage todescend when the pressure on the opposite sides of the piston isequalized.

5. In a balanced pressure fluid-actuated elevator, an v operatingcylinder provided `with aplston, a' piston rod connected to the upperside of said piston and projecting upwardly throughastufling box in theupper end of the cylinder, an elevator cage or platform connected `tothe upper end of the piston rod, saidcage being so constructed thatpermanent weights can be added thereto or taken away therefrom to varythe permanent weightimposed Von the piston rod, a supply pipe leadingfrom a supply of liuid under pressure and communicating with the lowerend of the cylinder, so as to cause pressure j to be exerted on thelower side of the piston constantly, andra two-way valve for exhaustingfluid from the upper side of the piston to permitthe cage to ascend andfor Y introducing fluid onto the upper side of the piston, to cause thecage to descend.

`6. In a pneumatic elevator, wherein the cylinder is underneath theplatform, a source of` compressedair connected directly to the lower endof the cylinder, andconnected to the upper end "of the cylinder, bymeans of a two-way Y valve, permitting the flow of compressed air intoor out of the upper end vof the cylinder, the combined weight of theempty platform and piston rod being sufficient to" cause the cage todescend, when the compressed air is admitted to both ends of thecylinder.

7.` Iny a pneumatic elevator of the character described, a balancedpressure air hoist arranged topush on the piston rod, the motivepressure` being connected to the lower `end of the cylinder, thebalancing pressure being admittedito andlexhausted from the upper end!of thefcylinder, and the piston the lower end of the cylinder,thebalancing pressure being connectedby means of a two'- 'Way valve tothe upper end of the cylinder, and the piston rod and empty cage having15 sulicient Weightto return the empty cage agamst the unbalanced forcesof the hoist,

Vwhen the balancing pressure is admitted to the upper end of the hoist.

In testimony whereof I hereunto alix my 20 signature in the presence oftwo Witnesses, this ninth day of March, 1909.

GEORGE F. STEEDMAN. Witnesses Gno. E. HOFFMANN, WILLIAM F. HARRISON.

